Disclosed herein are processes for phase-selective gelation using alkylated aromatic acid compounds.
The topic of phase-selective gelation has attracted recent interested because of potential applications in environmental remediation, such as containment of oil spills, phase-selective isolation of toxic organic liquids from complex mixtures, or the like. The design of phase selective gelators is often a challenge because of the strong ability of water to participate in hydrogen-bonding, which can interfere with the gelation process.
Polymeric gels have also been employed as oil-water separators. Polymeric gels, however, can require high gelator loading and are not generally thermo-reversible, and recovery of the oil phase from the gelator or vice versa is difficult, if not impossible. For this reason of recyclability of the gelator agent, a low molecular weight compound is preferable.
An organogel is a three-dimensional network of non-covalently interacting molecules with interstitial spaces filled by organic liquid. Low molecular weight organogels are a rapidly developing class of such materials, in which small molecular building blocks self-assemble into hydrogen-bonded assemblies that can form a three-dimensional network capable of rigidifying entire fluids at very low concentrations. The use of organogel materials is diverse and spans many applications such as medicine, electronics, printing, personal care, and environmental remediation.
The “bottom up” self-assembly of molecular building blocks into nanostructured materials has attracted significant interest for advanced materials research. Nanostructured materials with controlled size, shape, and function are important for numerous industrial applications. Low molecular weight organogels are a rapidly developing class of such materials, in which small molecular building blocks self-assemble into hydrogen-bonded assemblies that can form a three-dimensional network capable of rigidifying entire fluids at very low concentrations. The use of organogel materials is diverse and spans many applications such as medicine, electronics, printing, personal care, and environmental remediation. Although a large number of organogelator compounds have been reported by many researchers, the rational design and synthesis of new organogelators remains a significant challenge since the gel properties in a given liquid cannot be predicted from the molecular structures alone. In addition, not all self-assembling nanostructures form gels when placed in contact with a liquid.
While known compositions and processes are suitable for their intended purposes, a need remains for materials and processes for separating oil-water mixtures. In addition, a need remains for materials and processes for containing, separating, and recovering a desired or undesired phase from a mixture of two immiscible liquid phases, such as an oil spill in water. Further, a need remains for such materials and processes wherein the materials used for the phase separation can be recycled. Additionally, a need remains for such materials and processes wherein the materials have self-complementary functional groups that can self-assemble readily by a “bottom-up” fabrication strategy to produce well-defined nanostructures and potentially higher-order network structures; bottom-up fabrication strategies entail growing structures of the desired shape and dimensions from smaller building blocks, also referred to as self-assembly. A need also remains for such materials and processes wherein in some embodiments the separation process, i.e., gelation, may be triggered by external stimuli, such as heat, light, ultrasound, chemical stimuli, mechanical stimuli, or the like. In addition, a need remains for such materials and processes wherein in some embodiments the recovery process is reversible, which facilitates recovery of the oil, the water, and the gelator.